This invention relates to a lock set including an axial pin tumbler lock and a mechanical key with an electronic identification chip.
Axial pin tumbler locks have been used for many years, and a variety of such locks have been manufactured. Typical of such locks is the pin tumbler lock disclosed in U.S. Pat. No. 3,451,819 issued Nov. 24, 1970 to W. J. Kerr for an Axial Pin Tumbler Lock wherein the lock is operated by a single key. Monahan in U.S. Pat. No. 3,422,646 issued Jan. 21, 1969, discloses a pin tumbler lock which permits resetting of the lock. Another type of resettable axial pin tumbler lock is disclosed in Reissue Patent No. 28,319. An axial pin tumbler lock which may be mechanically reset to provide many distinct combinations is also disclosed in U.S. Pat. No. 4,233,828. Yet another resettable axial pin tumbler lock is disclosed in McGee, U.S. Pat. No. 4,858,456. Thus, there are numerous types of axial pin tumbler locks available. Such locks are especially popular for use in vending machines and the like. Such locks are more useful for vending machines provided the combination of the lock may be altered from time to time to improve the security of the lock.
Recently, enhanced security requirements have led to the development of locks which incorporate the mechanical characteristics of tumblers which interact with a bitted key and the security of an electronic combination associated with a chip carried on the key for the lock. Typically a lock with a chip incorporated on the key will, upon insertion of the key into the lock, provide an appropriate electronic combination or signal to release a lock bolt as well as a mechanical combination to align the tumblers of the lock to permit actuation thereof by the key. Gokcebay et al. in U.S. Pat. No. 5,367,295 entitled "Conventional Mechanical Lock Cylinders and Keys with Electronic Access Control Feature" discloses a combination mechanical and electronic access controlled lock. In U.S. Pat. No. 5,367,295, the key is inserted into a keyway. A ground connection is made with a cylinder and a spring loaded contact within the lock engages the key in a manner which enables the chip mounted on the key to be "read." Each of the reference patents discussed above is incorporated herewith by reference.
With the advancement of lock design and the concept of combining electronic as well as mechanical features in a single lock, there has remained a desire to provide a construction capable of changing the combination of the lock, mechanically as well as electronically. Further, there has remained a desire to provide a mechanical and electrical lock set construction which is easy to manufacture, may be incorporated in existing lock designs and which may be adapted for use with axial pin tumbler locks. These and other incentives inspired the present invention.